Method and system for delivering a medical electrical lead within a venous system

ABSTRACT

A loading device for loading a guide wire within a medical electrical lead that includes a navigation portion, having an outer portion, and extending from a front end to a back end, and having an opening formed at the back end. An engagement cavity receives and properly orientates the lead distal tip to align the lumen of the lead with the opening of the navigation portion during the loading of the guide wire within the lead. A first side wall is spaced from a second side wall to form a slot extending along the outer portion from the front end to the back end of the navigation portion, and the guide wire is advanced through the slot as the lead having the guide wire loaded therein is removed from the loading device.

RELATED APPLICATIONS

This application is a continuation-in-part of commonly assigned U.S.patent application Ser. No. 09/822,678 filed Mar. 30, 2001, which isrelated to, and claims the benefit of provisionally-file U.S. patentapplication Ser. No. 60/193,695, filed Mar. 31, 2000, and entitled“Intraluminal Visualization System with Deflectable Mechanism”, both ofwhich are incorporated herein by reference in their entireties.

Cross-reference is hereby made to commonly assigned related U.S.Applications, filed concurrently herewith, Ser. No. 10/131,436, entitled“IMPROVED SYSTEM AND METHOD FOR POSITIONING IMPLANTABLE MEDICAL DEVICESWITHIN CORONARY VEINS”, and Ser. No. 10/131,388, entitled “METHOD ANDSYSTEM FOR DELIVERY OF A MEDICAL ELECTRICAL LEAD WITHIN A VENOUSSYSTEM”.

BACKGROUND OF THE INVENTION

The present invention relates generally to delivery of various devicesor agents into a targeted area of the body, and in particular, thepresent invention relates to a method and apparatus for accuratelydelivering medical devices such as leads, electrophysiology catheters,and therapeutic agents into large-organ vessel systems such as thecoronary vasculature.

In treating conditions such as arrhythmia, one technique is to destroyor damage heart tissue that causes or is involved with the arrhythmia bysuitably heating the tissue, e.g., by applying a laser beam orhigh-frequency electrical energy such as radio-frequency (RF) ormicrowave energy.

For such treatment to be effective, the location of the tissue sitecausing or involved with the arrhythmia must be accurately determined inorder to be able to contact heart tissue adjacent the desired locationwith a tissue-destroying device. A high degree of accuracy indetermining this site is paramount so that an excessive amount of viabletissue is not destroyed adjacent the site. For example, the averagearrhythmogenic site consists of about 1.4 cm² of endocardial tissue,whereas a re-entrant site might be much larger. RF ablation techniquesproduce lesions about 0.5 cm² of diameter, so a number of lesions aretypically generated in order to ablate the area of interest. If the siteis not accurately mapped, much of the viable tissue surrounding the sitewill be unnecessarily destroyed.

To determine the location of the tissue to be ablated, it is widelyknown to use elongated intravascular signal sensing devices that areadvanced through the patient's vasculature until the distal portions ofthe device are disposed within one or more of the patient's heartchambers, with one or more electrodes on the distal portion of thedevice in contact with the endocardial lining. Such devices may also beadvanced within a patient's coronary artery, coronary sinus, or cardiacvein. Sensing devices such as those disclosed in U.S. Pat. No. 5,967,978to Littmann et al., and combination sensingablation devices such asthose disclosed in U.S. Pat. No. 6,002,956 to Schaer are typical.

Guiding catheters such as those disclosed in U.S. Pat. Nos. 6,021,340and 5,775,327 to Randolph et al. may be used to rapidly advance suchdevices into a patient's cardiac vein draining into the coronary sinus.A particular advantage of the catheters disclosed in these references isthe presence of an inner lumen and distal port on the catheter shaft,which, in conjunction with a distal balloon, allows for the deploymentof contrast fluid distal to the distal end of the catheter forvisualizing the venous structure.

The following U.S. Patents discuss related devices and methods for theiruse: U.S. Pat. Nos. 5,509,411, 5,645,064, 5,682,885, 5,699,796,5,706,809, and 5,701,298, each to Littmann et al; U.S. Pat. Nos.5,881,732 and 5,645,082, each to Sung et al; U.S. Pat. No. 5,766,152 toMorely et al; U.S. Pat. Nos. 5,782,760 and 5,863,291, each to Schaer;U.S. Pat. No. 5,882,333 to Schaer et al., and U.S. Pat. No. 6,122,552 toTockman et al.

However, despite the advantages of these sensing devices and guidingcatheters, it remains quite difficult to accurately and reliably contactthe various curved shapes one encounters in the endocardial lining. Thisis due to the frequent inability to customize the shape of their distalportion, or at least the inability to instantaneously and accuratelyadjust their shape upon demand during deployment to conform to the shapeof the tissue of interest.

Concerns similar to those described above are associated with theplacement of leads within the heart and other areas of the coronaryvasculature. For example, pacemakers, defibrillator/cardioverters, andother implantable medical device (IMDs) may employ one or moreelectrodes that are maintained in contact with a patient's heart muscleand through which electrical stimulation of the heart muscle isachieved. Such devices typically employ a flexible conductive lead thatconnects a remotely positioned and implanted power source to the one ormore electrodes. Secure placement of the electrodes in the selectedheart chamber (typically the right atrium) or in a coronary vein orartery is required to assure appropriate and reliable depolarization or“capture” of cardiac tissue by electrical stimuli delivered by the IMD.

Many problems exist with reliably and accurately placing medicalelectrical leads and other similar devices such as catheters within theheart and associated vasculature. For instance, when placing transvenousleads or catheters, it is often difficult to engage the coronary sinusand sub-select the proper vessel into which the lead or catheter is toeventually be placed. Moreover, once placed, transvenous devices sufferfrom a relatively high rate of dislodgment from sites adjacent to, oron, the epicardium. Such dislodgement may result in a loss of captureor, at best, a reduction of the degree of electrical coupling betweenthe electrode and the myocardium. More accurate and secure placement ofthe lead or catheter would not only reduce the difficulty and timeassociated with lead placement, but would reduce the risk of subsequentdislodgment as well.

There thus is a need for a method and system for placingintralumenally-deployed devices such as electrophysiology catheters andleads into selected areas of the coronary vasculature in a highlyaccurate and reliable fashion.

SUMMARY OF THE INVENTION

The present invention is directed to loading device for loading a guidewire within a medical electrical lead having a lead distal tip and alumen for receiving the guide wire. The loading device includes anavigation portion, having an outer portion, and extending from a frontend to a back end, and having an opening formed at the back end, and anengagement cavity that receives and properly orients the lead distal tipto align the lumen of the lead with the opening of the navigationportion during the loading of the guide wire within the lead. A firstside wall is spaced from a second side wall to form a slot extendingalong the outer portion from the front end to the back end of thenavigation portion, and the guide wire is advanced through the slot asthe lead having the guide wire loaded therein is removed from theloading device.

In accordance with another aspect of the present invention, a system fordelivering a medical electrical lead within a coronary venous systemincludes an introducer kit for establishing venous access to thecoronary venous system, a plurality of delivery sheaths, eachcorresponding to a desired approach to a coronary sinus of the coronaryvenous system, for establishing a navigation pathway within the coronaryvenous system through the venous access, and a hemostasis valve coupledto a delivery sheath of the plurality of delivery sheaths. A loadingdevice that is utilized to load a guide wire within a lead lumen of thelead includes a navigation portion, having an outer portion, andextending from a front end to a back end, and having an opening formedat the back end. An engagement cavity of the loading device receives andproperly orientates a lead distal tip during the loading of the guidewire within the lead, and a first side wall is spaced from a second sidewall to form a slot extending along the outer portion from the front endto the back end of the navigation portion, so that the guide wire isadvanced through the slot as the lead having the guide wire loadedtherein is removed from the loading device. The guide wire guidesdelivery of the distal tip of the medical electrical lead to a targetsite within the coronary venous system through the hemostasis valve andthe delivery sheath, and, subsequent to the distal tip being deliveredto the target sight, the hemostasis valve is advanced over the connectorof the medical electrical lead to remove the hemostasis valve from themedical electrical lead.

In accordance with yet another aspect of the present invention, a methodof delivering a medical electrical lead within a coronary venous systemincludes establishing venous access to the coronary venous system usingan introducer tool kit, choosing a delivery sheath from a plurality ofdelivery sheaths corresponding to a desired approach to a coronary sinusof the coronary venous system, and positioning the delivery sheathwithin the venous access. The lead is inserted within a loading device,and a guide wire is inserted within a navigation portion of the loadingdevice to direct the guide wire within a lumen of the lead. The guidewire is advanced through a slot, formed by a first side wall spaced froma second side wall and extending along an outer portion of thenavigation portion, to remove the lead having the guide wire insertedtherein from the loading device. The distal tip of the medicalelectrical lead is inserted within the delivery sheath, and advancementof the distal tip of the medical electrical lead is guided to a targetsite within the coronary venous system using the guide wire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side cutaway view of a delivery sheath of the presentinvention;

FIG. 1B is a cross-sectional view of a delivery sheath of the presentinvention;

FIGS. 2A-2B are side and cross-sectional views, respectively, of aballoon catheter of the present invention;

FIG. 3 is as side view illustrating components included in both thedeflection mechanism and micro-deflection mechanism of the presentinvention;

FIGS. 4A-4B are various views of a deflection mechanism handle of thepresent invention;

FIG. 5 is a cross-sectional side view of three components of the presentinvention: a deflection mechanism, an outer sheath, and a ballooncatheter with an inflated distal balloon and a deflected distal end;

FIGS. 6A-6D are various views of a micro-deflection mechanism handle ofthe present invention;

FIGS. 7A-7B are two embodiments of deflection and micro-deflectionmechanisms detailing two notch configurations;

FIGS. 8A-8D are additional embodiments of deflection and microdeflectionmechanisms of the present invention, detailing additional notchconfigurations;

FIG. 8E is a cross-sectional view of a deflection and micro-deflectionmechanism having a tubular member with an irregular wall thickness toprovide a preferred bending direction;

FIGS. 9-11 depict a method for accurately placing an endocardial leadinto the cardiac venous system through the coronary sinus ostium using asystem of the present invention;

FIG. 12 is a plan view of a steerable catheter that may be used as analternative deflection mechanism to navigate the balloon catheter 200into the coronary sinus;

FIGS. 12A through 12C illustrate various deflection positions of thedistal tip of the steerable catheter of FIG. 12;

FIG. 13 is a schematic diagram of a tool kit used to establish venousaccess in a system for delivering medical devices within a coronaryvenous system according to the present invention;

FIG. 14 is a schematic diagram of a guide wire clip of a tool kitaccording to the present invention;

FIG. 15 is a schematic diagram of a wire clip of a tool kit according tothe present invention;

FIG. 16 is a schematic diagram of a rotatable hemostasis valve (RHV) ofa tool kit according to the present invention;

FIG. 17 is a schematic diagram of a delivery sheath for delivering amedical electrical device within a coronary venous system, according tothe present invention, from a right-sided venous access point to acoronary sinus;

FIG. 18 is a schematic diagram of a delivery sheath for deliveringmedical devices within a coronary venous system, according to thepresent invention, from a left-sided venous access point to a coronarysinus;

FIG. 19 is a plan view of a medical electrical lead having a lumen forreceiving a stylet or a guide wire for delivering a medical electricaldevice within a coronary venous system according to the presentinvention;

FIG. 20 is a schematic of a guide wire atraumatic formable tipprotruding from a lead distal tip of a medical electrical lead andnavigating from the coronary sinus into a branch vein;

FIG. 21 is a planar view of a stylet wire inserted within a medicalelectrical lead in a system for delivering medical devices within avenous system according to the present invention;

FIG. 22 is planar side view of a medical electrical lead having a lumenfor receiving a stylet wire and a guide wire in a system for deliveringmedical devices within a venous system according to the presentinvention;

FIG. 23 is a cross-sectional side view of a lead distal tip of themedical electrical lead of FIG. 22;

FIG. 24 is a schematic diagram of a loading device in a system fordelivering medical devices within a venous system according to thepresent invention;

FIG. 25 is a cross-sectional view of the loading device of FIG. 24;

FIG. 26 is a schematic diagram of a lead connector fixedly insertedwithin the loading device of FIG. 24;

FIG. 27 is an isometric diagram of an alternate embodiment of a loadingdevice in a system for delivering medical devices within a venous systemaccording to the present invention;

FIG. 28 is a front planar view of the loading device of FIG. 27 in aclosed position;

FIG. 29 is a cross-sectional side view of a loading device according tothe present invention, taken along cross-sectional lines VII—VII of FIG.28;

FIG. 30 is a front planar view of the loading device of FIG. 27 in anopen position;

FIG. 31 is a top perspective view of an alternate embodiment of aloading device for loading a guide wire within a medical electrical leadaccording to the present invention;

FIG. 32 is a cross-sectional side view of a loading device according tothe present invention, taken along cross-sectional line IV—IV of FIG.31;

FIG. 33 is a top planar view illustrating insertion of a guide wirewithin a medical electric lead using a loading device according to thepresent invention;

FIG. 34 is a cross-sectional side view of a loading device according tothe present invention, taken along cross-sectional lines V—V of FIG. 33;

FIG. 35 is a top planar view illustrating insertion of a guide wirewithin a medical electric lead using an alternate embodiment of aloading device according to the present invention;

FIG. 36 is a schematic diagram of positioning of a guide wire positionedwithin a branch vein;

FIG. 37 is a schematic diagram of a hemostasis valve according to thepresent invention in an attached position;

FIG. 38 is a schematic diagram of a hemostasis valve according to thepresent invention in an unattached position;

FIG. 39 is partial section plan view of a hemostasis valve according tothe present invention; and

FIG. 40 is a flowchart of a method of delivering a medical electricallead within a coronary sinus according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

This invention is a method and system for intralumenal visualization anddeployment of implantable medical devices (IMDs) such as transvenousleads, electrophysiology catheters and the like to various targetedregions of the body. The inventive system includes a sheath, a ballooncatheter and associated deflection mechanism, and a micro-deflectiondevice for highly accurate placement of the lead, catheter, or otherdevice once the area of interest has been visualized.

In the following pages we provide a component-by-component descriptionof a preferred variation of the invention followed by a description of aprocedure for using this system to place a transvenous lead into thecoronary veins. Although we detail an exemplary set of system componentsand a method for its use, additional system configurations, adaptations,and methods of use, some of which are also described herein, are withinthe scope of the invention.

In general, the intralumenal visualization system and micro-deflectiondevice of the present invention includes a deflectable catheter thatincludes an inflatable member such as a balloon, and is insertable intoa lumen of a delivery sheath. This sheath may be inserted into the bodyvia a typical introducer as will be described in more detail. In apreferred use, a delivery sheath is guided by a deflection mechanism sothat it may engage the coronary sinus ostium. A balloon catheter isinserted through the delivery sheath and into the coronary sinus orthrough a delivery sheath over a guide wire so that an occlusivevenogram may be rendered and the balloon catheter is removed. Next, alead with a micro-deflection mechanism is inserted into the sheath lumenso that the lead may be deployed at the desired location in the coronaryveins. The micro-deflection mechanism disposed within the lead is usedto provide rigidity to the lead and to allow a means to sub-selectcoronary vessels. The sheath preferably may be splittable along itslongitudinal length so that it may be removed around the lead withoutdisturbing it.

Delivery Sheath

FIG. 1A is a cutaway side view depicting a variation of the deliverysheath described above. As best seen in FIG. 1A, sheath 100 comprises anelongate shaft 102 containing a central lumen 104 throughout its length.The working length of sheath 100 comprises a distal section 110 and aproximal section 120, each of which comprises a polymeric materialhaving differing flexibilities as described below. A distal end 112 ofsheath 100 disposed adjacent distal section 110 also comprises theworking length.

Near the proximal end of sheath 100, a hub 114 may be affixed toproximal section 120 by an adhesive or other suitable means. We preferan ultraviolet-curable adhesive sold by Loctite Corp. of Rocky Hill,Conn. under the name UV 4201. We also prefer an adhesive sold by Dymaxcorp. of Trorrington, Conn. under the trademark DYMAX. Hub 114 is madefrom any suitable medical-grade polymer, and is preferably injectionmolded and longitudinally scored or perforated so that it may be removedfrom around a device without disturbing that device. It may be molded insitu onto the proximal section 120 of shaft 102.

Hub 114 has an opening large enough to accommodate a special rotatablehemostatic valve (RHV) 118, to which it is detachably secured by, e.g.,an annular ring on the valve 118 inner diameter. A central lumen 124 inRHV 118 is aligned and in fluid communication with the lumen of shaft102. Lumen 124 has a diameter large enough to accommodate a ballooncatheter and a typical lead connector, such as an IS-1-type connector.An optional side arm (not shown) may be disposed on RHV 118 in fluidcommunication with lumen 124. RHV 118 may also be splittable via ascoring or perforation as described above.

An annular polymeric collar 116 is disposed on the outside diameter ofRHV 118 distal portion proximal to the point where hub 114 meets RHV118. In this embodiment, rotation of collar 116 locks the RHV 118 to thehub 114.

FIG. 1B is a cross-sectional view of the delivery sheath of FIG. 1A. Asshown in FIG. 1B, a cross-section of shaft 102 in the distal section 110reveals shaft lumen 104. The inner diameter of shaft 102 will varydepending on the outer diameter of the balloon catheter and the lead,each of which should be capable of passing through lumen 104. Typicallythe shaft inner diameter is between about 0.080 and 0.110 inch; morepreferably it is about 0.098 inch. Likewise, the outer diameter of shaft102 is typically between about 0.090 and 0.130 inch; more preferably itis about 0.118 inch. We prefer the outer diameter of shaft 102 to be assmall as possible while still maintaining acceptable performance levelsaccording to the application for which the shaft is used. We also preferthat shaft 102 generally maintains a constant inner diameter throughoutits length to provide a smooth and continuous step-free profile for thepassage of various devices and materials therethrough as describedherein.

Tubing comprising distal section 110 and proximal section 120 willtypically be polymeric, and is preferably any typical medical grade,biocompatible tubing with the appropriate performance characteristics asdescribed herein. An especially desirable material is an extrudedpolyether block amide of the type sold by Atochem North America, Inc.,Philadelphia, Pa. under the trademark PEBAX.

Distal and proximal sections 110 and 120, respectively, are constructedof tubing having a durometer hardness ranging from about 20D to 100D(shore). The working length of shaft 102 preferably is composed ofmaterials having two or more stiffnesses, although shaft 102, having asingle stiffness value throughout its length is within the scope of theinvention.

In one embodiment, proximal section 120 comprises a relatively highstiffness material (typically about 72D) in comparison to the moreflexible distal section 110 (typically about 40D). Although not shown inthe view of FIG. 1B, distal section 110 and proximal section 120 may becomprised of a DACRON (E. I. du Pont de Nemours and Company, Wilmington,Del.) braid with a TEFLON (E. I. du Pont de Nemours and Company,Wilmington, Del.) liner. The braid is surrounded by the PEBAX tubing asdescribed above, which renders the proximal section 120 of shaft 102generally stiffer and less flexible than distal portion 110.

Distal end 112 is preferably a soft, atraumatic tip made form arelatively low stiffness polymeric material so to prevent injury to theintima of the vessel walls or to other tissue. We have found aneffective material for distal end 112. A material well-suited for thedistal end is a thermoplastic polyurethane elastomer such as PELLETHANE(Dow Chemical Co., Midland, Mich.) or the like.

According to one aspect of the invention, distal portion 110 may beradiopaque. This can be achieved by the inclusion of radiopaque metalsor their alloys into the structure, or more preferably by incorporatingradiopaque powders such s BaSO, BiCO, etc. into the polymer comprisingdistal portion 110. Distal end 112 is preferably more radiopaque thandistal portion 110. This can be achieved by the incorporation of greaterquantities of radiopaque powder, for instance, into the tubing, or bythe use of a different material having greater radiopacity than thatused in distal portion 110. This radiopaque feature allows the user tomore readily visualize these portions of sheath 100 under fluoroscopy.

The entire length of shaft 102 (from distal end 112 to the far proximalend of RHV 118) is typically between about 40 and 60 cm, and ispreferably about 55 cm. Distal end 112 may be between about 0.2 cm and0.5 cm long, while distal section 110 is generally between about 5 and10 cm long, and is preferably about 8 cm long. Proximal section 120 isbetween about 35 and 50 cm long; preferably about 42 cm.

Both the working length of shaft 102 as well as the attached hub 114 maycontain a perforation or score 126 along their longitudinal axes.Alternatively, they may be otherwise configured to split so that theymay be opened and removed from around an inserted device such as a leador electrophysiology catheter without having to axially slide the sheath100 relative to the device. A special tool may be used to facilitatesuch splitting, or the sheath/hub (and even RHV 114) combination may besplit by hand without the aid of any special device. The splittablevalve and sheath combinations as described in U.S. Pat. No. 5,312,355 toLee is exemplary.

Balloon Catheter

Turning now to FIGS. 2A-2B, a balloon catheter 200 of the presentinvention is shown in side view and distal cross-sectional view,respectively. This catheter is largely similar to the guiding cathetersdisclosed in U.S. Pat. Nos. 6,021,340 and 5,775,327 to Randolph et al,the entirety of each of which are incorporated herein by reference, aswell as the VUEPORT family of balloon occlusion guiding catheters soldby Cardima, Inc. of Fremont Calif.,

Catheter 200 is designed to pass through the central lumen 104 ofdeployment sheath 100, and reach the therapeutic site as a combined unitwith sheath 100 and deflection mechanism 300.

As shown in FIGS. 2A and 2B, balloon catheter 200 generally includes anelongated shaft 202, a distal shaft section 204, a proximal shaftsection 206, and an inner lumen 208. A female luer lock 210 may bedisposed on the proximal end of shaft 202 and secured by a suitableadhesive 212, such as UV-curable Loctite 4201.

A distal port 214 is provided in the distal end 216 of the cathetershaft that is in fluid communication with the inner lumen 208. Proximalof distal end 216 is an occlusion balloon 211 axially disposed in thedistal section 204 about catheter shaft 202. The catheter shaft 202 isprovided with an inflation lumen 209 that extends through the shaft 202to the interior of the balloon 211 to direct inflation fluid therein.

On the proximal end of catheter 200, proximal to luer lock 210, is amultiarm adapter or hub 222 that terminates in a Y-adapter or hemostasisvalve 232 and a proximal port 218 for passage of a deflection mechanismtherethrough as described later.

A first sidearm or port 224 on adapter 222 (shown in partial crosssection in FIG. 2A) facilitates introduction of inflation fluid intoinflation lumen 209. A stopcock 228 on first sidearm 224 that allowsballoon 221 to stay inflated once the proper volume of fluid (such asair) has been introduced via syringe 230 is disposed adjacent stopcock228. Inflation lumen 209 is disposed in port 224 and extends distallyinto shaft 224 to facilitate inflation of balloon 211 as describedabove.

A second sidearm or port 226 may also be disposed on hub 222, and may bein direct fluid communication with large inner lumen 208. Inner lumen208 is used for housing devices such as a deflection mechanism or thelike. Once balloon 211 is inflated, the second port 226 may be used forintroducing contrast media or similar material through lumen 208 and outthe distal port 214 for visualization of a section of interest in thebody, such as an organ lumen or the cardiac venous system, for instance.

Not shown is a rotatable hemostatic valve (RHV) that may be housed inthe proximal center port 218 and that can accept devices such as adeflection mechanism described below. This RHV is capable of sealingonto the deflection mechanism to prevent fluid leakage and may be partof a duostat modified to comprise a single RHV and two sideports. Otherconfigurations, of course, are possible.

Shaft 202 of balloon catheter 200 is of a sufficient size so that it mayreadily pass through the lumen 104 of sheath 100. Ideally, we prefer theouter diameter of shaft 202 to be between approximately 0.050 inch and0.100 inch. More preferably, it is between 0.060 inch and 0.080 inch,and most preferably is about 0.074 inch.

The diameter of inner lumen 208 preferably is large enough to allow freepassage of contrast media or other material therethrough so thatvenograms and similar diagnostic procedures may be readily accomplished.It should also be large enough for the passage of a deflection mechanismas discussed below in greater detail. Finally, lumen 208 should allowthe free passage of contrast media or other agents therethrough whileoccupied by a device such as a deflection mechanism. In general, weprefer that inner lumen have a diameter of between 0.030 inch and 0.080inches, and is preferably about 0.048 inch. Likewise, inflation lumen209 preferably has a diameter of between about 0.005 inch and 0.020inch, and preferably is about 0.014 inch.

The balloon catheter shaft 202 preferably comprises PEBAX tubing havinga durometer hardness of between about 60D and 80D, preferably about 72D.Preferably, shaft proximal section 206 has a heat shrink tubing disposedon the outer surface thereof. Preferably, this heat shrink tubing ispolymeric and is comprised of clear polyolefin or the like. Distal tip216 is preferably a soft, atraumatic tip made of a relatively flexiblepolymeric material similar in composition and stiffness to distal tip112 of sheath 100. In one embodiment, distal tip is radiopaque.

The working length of balloon catheter shaft 202, which includes thedistal tip 216, distal section 204, and proximal section 206, should bebetween about 50 cm and 90 cm, although it may be longer or shorterdepending upon the application. We especially prefer a working length ofapproximately 70 cm which can accommodate a distal tip 216 ofapproximately 0.5 cm, a distal section 204 of approximately 6 cm, and aproximal section 206 of approximately 63.5 cm.

The length of the entire catheter 200 in this embodiment (the workinglength of shaft 202 and the components disposed proximal of proximalsection 206 discussed above) should be about 77.5 cm. In general, weprefer that the balloon catheter shaft 202 be between about 15 cm and 20cm longer than sheath 100.

Of course, the absolute and relative lengths of each component ofcatheter 200 may vary considerably. The particular application in whichcatheter 200 and the entire system of the present invention is to beused will dictate the particular dimensions and materials for itsvarious components (as well as each of the components of the inventivesystem) described herein.

Occlusion balloon 211, when inflated, should have a diameter sufficientto seal the coronary sinus ostium. This inflated diameter will typicallybe between about 0.2 inch and 1.0 inches, and more preferably, betweenabout 0.4 inch and 0.8 inches. We prefer balloon 211 to comprise aninelastic or elastic polymeric material. Polyurethane (e.g. PELLETHANE80A durometer, World Medical, Inc., Miami Fla.) is especiallypreferable. The inner diameter of the uninflated balloon 211 typicallywill be between about 0.04 inch and 0.08 inches, and more preferablybetween about 0.056 inch and 0.070 inches. The balloon wall thicknesstypically will be between about 0.002 inch and 0.006 inches, and morepreferably about 0.004 inches. Finally, the balloon 211 length typicallywill be between about 6 mm and 14 mm, and more preferably between about8 mm and 12 mm.

Deflection Mechanisms and Micro-Deflection Mechanism

The deflection mechanism and the micro-deflection mechanism are twoseparate components of the present invention. Deflection mechanism 300is designed for use in the balloon catheter 200, and is similar in manyrespects to the micro-deflection mechanism 400, only larger.Micro-deflection mechanism 400 is designed for use in a variety ofapplications where precise control and deflection of a device such as alead, electrophysiology catheter, or other similar IMDs, is needed. Itssmall size relative to deflection mechanism 300 renders it useful in awide range of applications in which its small size and flexibility maybe relied upon.

FIG. 3 is a plan view illustrating components of both the deflection andmicro-deflection mechanisms, although it will be described in terms ofthe deflection mechanism 300 for discussion purposes. Deflectionmechanism 300 generally comprises a proximal section 304, a distalsection 306, and a distal tip 308. Adjacent the proximal section 304 ishandle 310, a preferred variation of which is shown in detail in FIGS.4A and 4B.

Deflection mechanism 300 is designed to be place through proximal port218 of the balloon catheter 200 and into the inner lumen 208 such thatthe deflection mechanism distal tip 308 generally reaches distal section204, and preferably distal tip 216, of balloon catheter shaft 202. Whenthe handle 310 is activated, the distal section 306 of deflectionmechanism 300 deflects in a predetermined fashion, thus deflecting thedistal section 204 of the balloon catheter in a similar fashion. In thisway, balloon catheter 200 (or any device into which deflection mechanism300 is disposed) may be torqued to conform to the particular lumen orcavity into which it is disposed.

Shaft 302 of deflection mechanism 300 comprises a tubular member such ashypotube 312, preferably made of metallic biocompatible material such asmedical grade stainless steel, titanium, nitinol, alloys of these, orany suitable material as known to those of skill in the art. Hypotube312 preferably has an outside diameter small enough to fit within innerlumen 208 of catheter 200 and is preferably less than 0.048 inch. Asshown in FIG. 3, hypotube 312 is beveled to form a strain relief 316 atthe distal end of hypotube 312. Of course, this particular configurationof hypotube 312, as well as other aspects of the FIG. 3 deflectionmechanism 300, is merely exemplary. Other configurations that serve thepurposes of this invention are within the scope of this disclosure aswell.

Disposed within a central lumen of hypotube 312 is a pull wire 320,which can be a stainless steel, titanium, nitinol or other metal oralloy or even polymeric wire which when pulled activates the deflectionof distal section 306 of deflection mechanism 300. Pull wire 320 isattached to a flat spring 322, which is disposed in the distal section306 of deflection mechanism 300. Spring 322 is attached to hypotube 312using any suitable attachment method, such as welding, brazing,soldering, adhesives, or the like as is known to those of skill in theart. Spring 322 may be brazed to hypotube 312 along braze zone 314 asseen in FIG. 3. Likewise, any similar suitable attachment techniques maybe used to attach pull wire 320 to spring 322. In one embodiment, thepull wire and spring are brazed to one another in braze zone 318 as seenin FIG. 3.

Distal deflection region 306 is preferably covered with compliantpolymeric medical grade tubing, such as polyester, PEBAX, andtetrafluoroethylene. Especially preferred is a polymer oftetrafluoroethylene hexafluoropropylene and vinylidene fluoride known byits acronym as THV. This prevents fluid intrusion into the deflectionmechanism.

In an especially useful variation of the invention in which the systemis used for implanting a lead, the balloon deflection mechanism 300 willbe of sufficient diameter to provide rigidity to the balloon catheter200 during introduction into the coronary sinus ostium. The curve reachand deflection range should be sufficient to provide easy introductioninto the coronary sinus ostium, and the entire assembly should provideadequate pull strength to deflect and torque the distal portion 204 ofballoon catheter shaft 202 during manipulation into the coronary sinusostium.

Turning now to FIGS. 4A-4B, a useful variation of handle 310 formanipulating deflection mechanism 300 is shown. Handle 310 includes body324 and activation mechanism 326. Activation mechanism 326 may bemanipulated by pushing distally or pulling proximally along alongitudinal axis of handle 310. The machined parts of these componentsmay be polymeric. For example, a thermoplastic such as the acetylhomopolymer DELRIN (E. I. du Pont de Nemours and Company, Wilmington,Del.) may be used for this purpose. The molded parts may be formed ofpolymeric materials such as ABS (acrylonitrile butadiene styrene) or thelike. A proximal end of pull wire 320 is disposed in a central lumen 328of handle 310 and affixed into handle by means known to those of skillin the art.

Handle 310 is preferably lightweight and ergonomically configured forsimple, one-handed operation. The deflection range (the maximum angulardisplacement the distal tip 308 undergoes when displaced from a straightand undeflected zero-degree position) may be between about 90 degreesand 180 degrees, preferably between about 100 degrees and 135 degrees.Further details of the features and versatility of distal section 306will be described in greater detail below, as well a detaileddescription of how deflection is achieved.

FIG. 5 depicts three components of the inventive system described abovein a partial cross-section. Deflection mechanism 300 with handle 310 isshown disposed in the inner lumen of balloon catheter shaft 202 via theproximal port 218 as previously described. In turn, the combinationdeflection mechanism 300 and balloon catheter 200 are disposed in thelumen 104 of sheath 100. In FIG. 5, the distal section of ballooncatheter shaft 202 is shown in a deflected state via the action of thehypotube/pull wire mechanism. Notice also that distal balloon 211 isinflated with fluid provided through balloon fluid port 224. An RHV 118for outer peel-away sheath 100 as discussed herein is seen as a flushport 130 disposed on RHV 118. For purpose of clarity, sheath hub 114 isnot shown.

In general, there is no limit to the size of the deflection mechanismsdescribed herein. All of the related components are readily scalable tolarger or smaller sizes than those disclosed here as would be apparentto one of ordinary skill in the art and as the particular applicationdemands.

Turning now to a more specific discussion of micro-deflection mechanism400 depicted generally in FIG. 3, the features of this element arelargely similar to those of deflection mechanism 300. The features aregenerally smaller so that they may be used within devices such as leads,electrophysiology catheters, and the like as will be described below.

The micro-deflection mechanism utilizes a hypotube configuration asshown in FIGS. 7A, 7B, and 8A through 8E. We prefer the outer diameterof the micro-deflection mechanism hypotube (not shown) to be betweenabout 0.012 inch and 0.030 inch; preferably between about 0.014 inch and0.026 inch; most preferably about 0.015 inch. This will allowintroduction of the hypotube into a conventional IS-1 lead connector, aswell as allow for movement of the hypotube within the entire length ofthe central lumen of a lead body without causing any undue stress ordamage to any of the lead or catheter components.

We also prefer that the micro-deflection mechanism 400 pull wire, whichis also preferably stainless steel or nitinol, have an outer diameter ofbetween 0.005 and 0.015 inches, and more preferably between about 0.006and 0.010 inches. Most preferably, the outer diameter is about 0.008inch.

During deflection, we prefer that the distal-most 10 mm to 30 mm of theassembly 400 deflect, which in a preferred application, will allow thelead into which assembly 400 is placed to engage the coronary sinusostium. Due to the smaller size and greater maneuverability, assembly400 may deflect through angles as high 360 degrees and even 450 degreesor more. Such a high angular deflection capability allows the mechanism400 (and the device into which it may be deployed) to create a tightloop. These high-angle deflections are especially useful inelectrophysiology applications in which the micro-deflection mechanism400 may be deployed in a mapping/ablation microcatheter to effectcircumferential ablation patterns and the like in areas such as thecardiac pulmonary vein.

FIGS. 6A-6D depict various components of an especially useful variationof micro-deflection mechanism 400 handle 414. As shown in FIG. 6A,handle 414 includes a body 416 and an activation mechanism 418 that maybe manipulated by pushing distally or pulling proximally axially along alongitudinal axis of handle 310. The handle has a relatively smallpreferred length that may be in the range of 2 inches. This scales wellwith the other, smaller components of micro-deflection mechanism 400,and also allows for simple, one-hand fingertip operation by a physician.Of course, the sizes may be sized as needed in a manner discussed above.

Micro-deflection mechanism 400 can be used to replace the fixedcurvestylet generally used to provide a deflectable lead or catheter. Thisdeflectable lead or catheter may be more precisely placed in thetargeted region of the cardiac venous system, overcoming the problems ofstate-of-the-art systems. In addition, the micro-deflection mechanismmay be used in conjunction with the other components of the inventivesystem describe herein for deflectable electrophysiological catheters.

Turning now to features that are common to both the deflection mechanism300 and micro-deflection mechanism 400 (hereinafter referred to in thisgeneric discussion as simply “deflection mechanism”, each operates onthe same principal based on a hypotube/pull wire assembly. The pull wireruns through the middle of the hypotube and is attached, via brazing orthe like, at the distal end of the deflection mechanism.

The hypotube is allowed to deflect in a predetermined pattern by aseries of slots, or kerfs, cut into the hypotube distal section. U.S.Pat. Nos. 5,507,725 to Savage et al, 5,921,924 and 5,441,483 both toAvitall, 4,911,148 to Snowski et al, 5,304,131 to Paskar, the entiretyof each which are hereby incorporated by reference, describe variousmedical devices in which some type of notch is used to effect deflection

FIGS. 7 and 8 depict two variations of notch patterns that are useful inthe present invention. Because of the scalability of these features,they are useful in both the deflection assembly 300 as well asmicro-deflection assembly 400.

In reference to FIGS. 7 and 8, and the following discussion, note thatdue to the drawing space constraints, the “proximal section” of thehypotube refers to a portion of the deflection mechanism that isproximal only in that it is disposed proximal to the correspondingdistal section. It is possible that a considerable length of thehypotubes depicted in FIGS. 7 and 8 exists proximal to the so-marked“proximal section”.

In FIGS. 7A and 7B, two hypotube/pull wire combinations are shown in topand side views, starting from the top of the page, respectively. FIG. 7Adepicts an assembly 700 in which a pull wire 704 is brazed, soldered, orotherwise affixed to the distal end of hypotube 702 at hypotube distalsection 708. Note that pull wire 704 is deployed inside hypotube 702.The pull wire is disposed in the interior of hypotube 702 all the way tothe hypotube distal section 708 where it is affixed to hypotube 702 asdescribed above. In general, pull wire 704 is affixed in handle 310 suchthat when the handle is activated, hypotube distal section 708 willdeflect on the same side on which notches 710 (or as discussed below,the reduced wall thickness of hypotube) are located.

Each notch or kerf 710 is progressively deeper as one moves from theproximal end 706 of hypotube 702 to the distal end 708. This particularfeature will cause the hypotube to deflect in a smooth consistent curve.Note that the spacing between notches 710 is constant, and the onlydimension of each notch 710 that changes its depth. The width remainsconstant. Each of these parameters may vary as performance requires.

Further, the centroids of each notch are aligned along a single,straight liner longitudinal axis as one moves from proximal section 706to distal section 708. This axis along which the notches are aligned maybe nonlinear. For instance, the axis may be sinusoidal to effect aserpentine deflection profile, with a constant or varying pitch, or theaxis may have some other curvilinear or even stepwise shape. Regardlessof whether the notch centroids are aligned along a linear or nonlinearaxis, the centroid of each notch does not have to line up along such anaxis.

Note also that the distance between adjacent notches as one moves fromone end of a notch to the other end of hypotube of FIG. 7A remainsconstant. That is, the longitudinal axes of the notches are parallel toone another. This aspect of the notches or kerfs may also changedepending upon the application.

Another variable that may affect the shape and performancecharacteristics of the assembly 700 is the depth to which the notches710 are cut into the hypotube. For instance, in the assemblies of FIGS.7A and 7B, the notches are cut completely through the wall thickness ofhypotube 702. This need not be the case. It is within the scope of theinvention to provide notches in hypotube 702 in which a discrete amountof material is removed from the hypotube without penetrating through thehypotube thickness. A wide variety of depth profiles and patterns inetching each notch is therefore envisioned.

Taking this concept one step further, hypotube 702 need not contain aseries of notches or kerfs to achieve the desired preferential distancedeflection shape and response. For instance, it is within the scope ofthe invention to preferentially machine or etch the bulk of hypotube 702in an asymmetric fashion so that when the pull wire 704 is activated,the distal section 708 of hypotube 702 deflects in a predeterminedpattern. In other words, the wall thickness of hypotube 702 can be madeto vary a function of length and/or circumferential position in patternsranging from a simple tapering pattern to complex patterns in whichcorrespondingly intricate and complex deflection shapes and resourcesmay be had. Such a concept can be used alone or in conjunction with theuse of notches or kerfs as described herein.

Each of the parameters described above, as well as other parameters suchas hypotube wall thickness, material selection, etc. may be chosen toeffect a particular deflection pattern and response depending upon theapplication for which the hypotube/pull wire assembly (such as assembly700) is intended. Furthermore, variations in many of these parametersfrom notch-to-notch may also be made. For instance, one notch may have arectangular profile, while another notch on the same hypotube may have acircular profile, etc.

Software may be utilized to aid the designer, by way of mathematicalalgorithms and the like, to ascertain the optimal profile for hypotube702 given a desired deflection shape, etc. For instance, a designer maybe able to choose the application for which the assembly is to be used,and the software may select a number of alternative shapes from whichthe designer may choose. Once a deflection shape is chosen, the softwarewill then calculate the optimal hypotube profile.

FIG. 7B shows an assembly 750 in which hypotube 752 and pull wire 754are arranged in a similar fashion to those described above and shown inFIG. 7A. The only difference in the assembly of FIG. 7B is that theconstant spacing between the notches 756 is larger than that in theassembly of FIG. 7A. This increased but constant spacing between notches756 results in hypotube 752 being slightly heavier, since less materialhas been cut away from the hypotube. When assembly 750 is deflected,this means that distal section 760 will deflect through a smaller anglewith a larger curve diameter (although the deflection shape willgenerally be similar as that of the deflected assembly 700 due to thesimilar size, shape, and orientation of the notches in each assembly)than that experienced by assembly 700 in FIG. 7A for a given deflectionforce.

Turning now to FIGS. 8A through 8E, additional variations of a notchpattern are shown (the pull wire is omitted for clarity). In FIG. 8A,hypotube 810 with proximal section 812 and distal section 814 contains aseries of linear notches 816 similar to those of FIGS. 7A and 7B, exceptthat each end of notches 816 contain a secondary notch 818 orientedgenerally perpendicular to notch 816. This notch design causes thedistal section 814 of hypotube 810 to deflect in a similar fashion asdescribed above, possibly with a tighter curve diameter.

The hypotube of FIG. 8B is identical to that of FIG. 8A, except that thenotch pattern begins closer to the proximal section 822 of hypotube 820.A longer length of hypotube distal section 824 will therefore deflectwhen activated by the pull wire.

FIG. 8C is a plan view depicting an embodiment of deflection mechanismwherein the notches are arranged in a non-linear manner. For example, asinusoidal pattern is depicted, although many other types of patternsare possible.

FIG. 8D is a plan view depicting an embodiment of deflection mechanismwherein the notches are of different shapes and sizes. For example, thenotches may be circular, triangular, rectangular, or any other patterndesired to allow the deflection mechanism to assume a desired shape whentension is applied to the pull wire. The notches may all have a uniformshape and size, or alternatively, may have different shapes and/orsizes.

FIG. 8E is a cross-sectional view depicting an embodiment of thedeflection member wherein the hypotube has walls that are not of aconsistent thickness. The thinner region of the wall defines a preferredbending direction when tension is applied to the pull wire. In oneembodiment, both a thinner wall thickness and the creation of notches inthe thinner region may be used to provide the deflection mechanism inthe hypotube or other tubular member.

The notches or kerfs described herein and shown in the figures, as wellas the varying wall thickness of the hypotube, may be created by anymeans know to those of skill in the art. They may be machines bytraditional, laser, electron-discharge, or similar machining methods,they may be chemically etched, etched using known photolithographictechniques, etc.

A particularly useful feature in the deflection mechanisms describedherein is the active control feature of the deflection mechanism handle(both handle 310 as well as handle 414). Once the handle activationmechanism is engaged to deflect the distal section as described above,the deflection can be reversed only by the positive input of a user todisengage the same activation mechanism. In one embodiment of thedeflection mechanism described above and shown in FIGS. 4A-4B and FIGS.6A-6D, release of the activation mechanisms 326 and 418 after thesemechanism are deployed results in the distal section remaining in adeflected position. Reversal of this deflection requires that thephysician-user retract the activation mechanism, whereupon the distalsection 306 will resume the undeflected state until the handle isactivated once again. This feature allows the physician-user tomanipulate other portions of the inventive system or to perform othertasks while the distal section 204 of balloon catheter 200, for example,remains in the intended deflected or undeflected state. Of course, it iswithin the scope of the invention to design the handle so thatactivation to deflect distal section is automatically reversed to returnthe distal portion to a default undeflected state. This may beaccomplished by a bias spring or equivalent mechanism that activateswhen the physician releases the positive input causing the initialdeflection. Such a design may also bias the distal end of the deflectionmechanism to automatically reverse to a default deflected position.

Another feature common to both handles 310 and 414 is the presence ofone or more limit stops that may be built into the handle. These limitstops are designed to prevent over-deflection of the deflectionmechanism.

Deployment of Cardiac Lead

Turning now to FIGS. 9-11, a particularly useful application for thesystem herein described is shown and is discussed below. In particular,a method for intravascularly deploying the system into the coronarysinus, obtaining an occlusive venogram, and accurately subselecting avenous branch and placing a cardiac lead therein is described.

To prepare for the procedure, balloon catheter 200 is inserted withinthe lumen 104 of outer sheath 100 to create a sheath/cathetercombination. A deflection mechanism 300 is advanced into the large lumen208 of the balloon catheter via proximal port 218 so that the distal tip308 of the deflection mechanism shaft 308 is generally disposed inballoon catheter shaft 202 near shaft distal tip 216 as previouslydescribe. This creates a combination sheath/catheter/deflectionmechanism system as shown in FIG. 5. Typically, a portion of shaft 202will extend out through and beyond the lumen 104 at the sheath 100distal end 112 for some length.

This three-component system is introduced into the patient's venoussystem through the cephalic, subclavian or femoral vein via aconventional introducer as known to those of skill in the art. Thephysician uses the introducer to dilate the selected vein and thenadvance the system through the introducer into the selected vein.

Typically under fluoroscopic guidance, the physician navigates thethree-component system through the vasculature to and through thesuperior vena cava 910 or inferior vena cava 940 (see FIG. 9) and intothe heart 900 right atrium 920. At this point, the distal tip 216 ofshaft 202 and distal balloon 211 engage the coronary sinus ostium. Thedeflection mechanism is used to help steer the shaft 202 distal tip 216into place. Balloon 211 is then inflated, and contrast is injected intothe coronary veins through the distal port 214 of shaft 202. Thiscreates an occlusive venogram for visualizing the coronary veins inadvance of placing the lead in the desired location.

Next, while balloon 211 is still in the coronary sinus, the outer sheath100 is advanced into the coronary sinus over the catheter shaft 202 sothat it may be available as a conduit for lead placement. Once thesheath 100 is in place, the balloon 211 is deflated and the ballooncatheter 200 and the associated deflection mechanism 300 are proximallywithdrawn from sheath 100, leaving sheath 100 alone in place in thecoronary sinus as shown in FIG. 10.

Next, the micro-deflection mechanism 400 is placed into a central lumenof a lead 600 so that the deflectable distal section of micro-deflectionmechanism 400 generally engages the distal section of the lead 600. Thecombination of these components is then advanced into the lumen 104 ofsheath 100 and into the coronary sinus ostium as seen in FIG. 11. Fromhere, the physician will activate the deflection mechanism to steer thelead/micro-deflection mechanism combination. In one embodiment, themicro-deflection mechanism may be used to subselect a venous branch intowhich the lead is to be permanently placed. Of course, the particulardeflection shape and characteristics of micro-deflection mechanism havebeen selected by the physician for optimal use in navigating the venoussystem and creating the shape for the lead to assume during leadplacement.

Once the lead 600 is placed and the pacing thresholds are acceptable,the RHV 118 is removed from the sheath and slid over the lead connector(alternatively, RHV 118 may be split). Next, preferably with the aid ofa special slitting tool such as a customized razor blade attached to thesheath 100, the sheath 100 and hub 114 are split along score 126 as thesheath is pulled away from the lead 600 and removed from the body.

Micro-deflection mechanism 400 may be withdrawn from the lead 600, afterwhich the lead 600 is the only component left in the body. Lead 600remains in place, and may be coupled to a pulse generator,cardioverter/defibrillator, drug delivery device, or another type ofIMD.

As discussed throughout the specification, the method outlined above ismerely exemplary of one way to deploy a cardiac lead according to thepresent invention. Many alternative applications for the invention arepossible. Significant variations from this technique may occur withinthe scope of the present invention.

For example, in one embodiment, the deflection mechanism that is adaptedto be inserted within the balloon catheter is a steerable catheter suchas an electrophysiology (EP) catheter. One example of a catheter havinga suitable steering mechanism is the Marinr catheter commerciallyavailable from Medtronic Corporation.

FIG. 12 is a plan view of a steerable catheter that may be used tonavigate the balloon catheter 200 into the coronary sinus. The catheter1000 is an anatomically-conforming, dual curve EP catheter used to senseelectrical signals in the heart and associated vasculature. The catheterincludes a shaft 1004 having an atraumatic distal end 1006 and aproximal end 1008. Shaft 1004 may have an outside diameter of less thanapproximately 0.06 inches and a length of about 50 mm to 110 mm.Proximal end 1008 is mounted to a handle 1010 having axially slidablemanipulator rings 1012 and 1013, and a rotatable lateral deflection ring1014 operably connected to proximal and distal manipulator wires carriedby the body of the catheter. Sliding manipulator rings 1012 and 1013cause a deflectable tip 1020 of catheter shaft 1004 to deflect as shownin FIGS. 12A and 12B between, for example, the solid-line anddashed-line positions of FIG. 12B. Rotating ring 1014 causes lateraldeflection of tip 1020 through the torquing action of a core wire asshown in FIGS. 12C.

A steerable EP catheter of the type shown in FIGS. 12 through 12C isadapted to be inserted within the inner lumen of the balloon catheter,which in turn, is inserted within the lumen 104 of the outer sheath 100to create an alternative sheath/catheter combination. As previouslydescribed, this assembly may be advanced into the chambers of the heart.Next, the EP catheter distal tip may be advanced beyond the distal endof the outer sheath to guide the balloon catheter into the coronarysinus. The range of motion provided by the steerable catheter as notedabove makes it particularly suitable for cannulating the coronary sinusand utilizing the balloon catheter to obtain a venogram in the mannerdiscussed above. Then the balloon catheter and the steerable catheterare removed from the sheath so that the sheath may be used to place anIMD with a microdeflection mechanism in the manner discussed above.

According to another aspect of the invention, the system describedherein may be used for deploying a wide array of devices in the coronaryvenous structure, the pulmonary venous structure, or any organ withlarge enough vessels for the introduction of the system. In addition,the system can be used in extravascular applications such as in thedeployment of cochlear implants, in body cavities, muscle tissue, andthe like.

The balloon catheter 200 can be used for the introduction of drugs orother media or agents within a very discrete region of a vessel. Notethat the balloon on the balloon catheter 200 described herein isoptional. The deflectable catheter may be used without a balloon, forimproved access and maneuverability.

With respect to the micro-deflection mechanism 400, due to its abilityto be scaled to a very small size, it may be used for interventions intothe spinal column, tiny vessels in the brain, liver, kidney, or anyother suitable organ. In addition, sensor such as electrodes forrecording signals and possibly ablating tissue may be incorporated intothe micro-deflection mechanism 400. Fiber optics for the introduction oflight for visualization or optical recording or sensing may beincorporated into either deflection mechanism.

The deflection mechanism may also be used to deliver drugs or othertherapeutic or diagnostic agents or materials as described above.

The intralumenal visualization system of the present invention mayalternatively be defined in terms of a navigation pathway tool kit. Thetool kit provides the operator with a choice of tools to select anapproach for the delivery of a medical electrical lead that is bestsuited for the patient receiving the lead. The navigation pathway isdefined as the combination of the delivery sheath, positioned to provideaccess to the coronary sinus, and the venogram that serves as a map ofthe coronary veins. The present invention also includes additional leadaccessory tools, with unique features, to facilitate both lead deliveryand stable lead implant while the delivery sheath is being removed.

Navigation Pathway Tool Kit

FIG. 13 is a schematic diagram of a tool kit used to establish venousaccess in a system for delivering medical devices within a coronaryvenous system according to the present invention. According to thepresent invention, a tool kit 10 for establishing venous access includesa percutaneous introducer kit 5, used to gain venous access via theknown Seldinger technique, and including a needle 1, a syringe 3, anintroducer guide wire 4, an introducer sheath 7, an introducer dilator9, and an introducer slitter 11.

According to the present invention tool kit 10 also includes at leasttwo different types of delivery sheaths, such as a right-sided venousaccess delivery sheath 21 and a left-sided venous access delivery sheath23, a delivery sheath dilator 22, a guide wire clip 6, and a deliverysheath slitter 24. Delivery sheath 21, which has a length ofapproximately 40 cm, extends from a proximal portion 14 to a distalportion 12 formed into a curvature suited for an approach to thecoronary sinus from a right-sided venous access point, while deliverysheath 23, which has a length of approximately 45 cm, extends from aproximal portion to a distal portion 13 formed into a curvature suitedfor an approach to coronary sinus from a left-sided venous access point.The general construction of such delivery sheaths is described above inconjunction with FIGS. 1A and 1B.

Delivery sheath dilator 22 is inserted within a lumen 37 at proximalportion 14 of delivery sheath 21, 23 in order to stiffen and straightendistal portion 12, 13 for insertion of delivery sheath 21, 23 into avenous system after access has been gained using percutaneous introducerkit 5.

Dilator 22 has a central lumen that extends along the entire length ofdilator 22, is open at both ends, and is of sufficient diameter to slideover introducer guide wire 4 once introducer guide wire 4 is insertedwithin the central lumen of dilator 22. Introducer guide wire 4, whichis approximately 0.035″ in diameter and has a j-shaped tip 18, issufficiently long, at minimum approximately 100 cm, in order tocannulate the coronary sinus.

Following introduction of guide wire 4 within the coronary vein usingthe Selldinger technique, and once dilator 22 is inserted withindelivery sheath 21 or 23 and delivery sheath 21 or 23, with dilator 22therein, has been inserted over introducer guide wire 4, dilator 22 isremoved. A distal tip 15 of delivery sheath 21, 23 is then directed intothe coronary sinus. In order to prevent dissection of the coronary sinuswhen advancing delivery sheath 21 or 23, tip 18 of introducer guide wire4 is first advanced distally through delivery sheath 21 or 23 andextended outward from distal tip 15 of delivery sheath 21 or 23 andadvanced within the coronary vein. Once guide wire 4 is positionedwithin the coronary vein, delivery sheath 21 or 23 is advanced overguide wire 4 with distal tip 15 being directed over introducer guidewire 4 through the coronary sinus and away from a wall of the coronarysinus.

FIG. 14 is a schematic diagram of a guide wire clip of a tool kitaccording to the present invention. As illustrated in FIG. 14, accordingto a preferred embodiment of the present invention, guide wire clip 6,such as product number 35110, commercially available from QosinaComponents, includes a first engagement arm 200 and a second engagementarm 202 extending from a compression portion 204. Engagement arms 200and 202 each include a number of engagement tabs 206 and 208,respectively, positioned along a respective front portion 210 and 212 ofengagement arms 200 and 202. When guide wire clip 6 is in a non-engagingopen position, as illustrated in FIG. 14, a back portion 214 ofengagement arm 200 is engaged against a back portion 216 of engagementarm 202.

FIG. 15 is a schematic diagram of a wire clip of a tool kit according tothe present invention. By applying appropriately directed pressure atgripping portions 218 and 220, engagement arms 200 and 202 arere-positioned to grip guide wire 4 between engagement tabs 206 and 208in an engaging closed position, as illustrated in FIG. 15. As a result,excess length of guide wire 4 can be looped and clipped to surgicaldrapes, for example, so that guide wire clip 6 secures the excess lengthof guide wire 4 to prevent the excess length of guide wire 4 fromentering the sterile field when guide wire clip 6 is in the closedposition. At the same time, while pressure applied by engagement tabs206 and 208 on guide wire 4 when guide wire clip 6 is in the closedposition attaches guide wire 4 to surgical drapes, for example,engagement tabs 206 and 208 minimize the pressure exerted by guide wireclip 6 on guide wire 4 so that guide wire clip 6 does not prevent somemovement of guide wire 4 through engagement tabs 206 and 208. In thisway, guide wire 4 can be repositioned without having to be removed fromguide wire clip 6.

It is understood that although guide wire 4 is shown in FIG. 15 as beinglooped through engagement tabs 206 and 208, guide wire 4 could also bepositioned between engagement tabs 206 and 208 in a non-looped manner.As a result, guide wire clip 6 assists in positioning excess length ofguide wire 4, in either a looped or a non-looped manner, to prevent theexcess length from entering the sterile field, while allowing guide wire4 to be re-positioned relative to guide wire clip 6.

According to an alternative embodiment of the present invention, distalportions 12, 13 of delivery sheaths 21 and 23 may be straight. Asteerable catheter 1002, illustrated in FIGS. 12, and 12A-C, is includedin this alternate embodiment of tool kit 10. Steerable catheter 1002,inserted within a lumen of straight delivery sheath imparts selectablecurvature to delivery sheath distal segment for directing deliverysheath distal tip 15 to the ostium of the coronary sinus. Steerablecatheter 1002 may replace dilator 22 and introducer guide wire 4 as ameans for inserting delivery sheath 21, 23 into the venous system anddirecting distal tip 15 to the coronary sinus.

As illustrated in FIG. 13, tool kit 10 of the present invention alsoincludes a venogram balloon catheter 20. Balloon catheter 20 isdelivered to the coronary sinus within lumen of delivery catheter 21, 23in order to obtain a fluoroscopic map, or venogram, of the coronaryvenous system. The general construction of balloon catheter 20 andmethod of use was described above in conjunction with FIGS. 2A-B.

FIG. 16 is a schematic diagram of a rotatable hemostasis valve (RHV) ofa tool kit according to the present invention. As illustrated in FIG.16, according to the present invention, a rotatable hemostasis valve(RHV) 27 of tool kit 10 includes a non-standard Touhy Borst valve 28, aside arm flush port assembly 26, and a non-standard male luer fitting 16(FIG. 39) within a locking collar 8. Proximal portion 14 of deliverysheath 21, 23 is terminated with a slittable hub 25 of delivery sheath21 or 23, such as the slittable hub described in U.S. Pat. No. 6,159,198to Gardeski et al., which is incorporated in its entirety herein.Slittable hub 25 includes non-standard female luer fitting 37 for theconnection of RHV 27. RHV 27 is connected to hub 25 prior to insertingdelivery sheath 21, 23 into venous system. According to the presentinvention, non-standard male and female luer fittings 16 and 37 have adiameter approximately twice that of standard luer fittings that arewell known in the art. Furthermore, Touhy Borst valve 28 has a largermaximum inner diameter (not shown) than standard Touhy Borst valves alsowell known in the art. The advantage of larger diameter luer fittingsand Touhy Borst valve 28 will be presented, with a more detaileddescription of RHV 27, below, in conjunction with FIGS. 38 and 39.

Hub 25 has an opening large enough to accommodate a special rotatablehemostatic valve (RHV) 27, to which it is detachably secured by, e.g.,an annular ring on the inner diameter of valve 27. A central lumen 33 inRHV 27 is aligned and in fluid communication with the lumen within ashaft 36. Lumen 33 has a diameter large enough to accommodate a ballooncatheter and a typical lead connector, such as an IS-1-type connector,for example. An optional side arm 26 may be disposed on RHV 27 in fluidcommunication with lumen 33. RHV 27 may also be splittable via a scoringor perforation as described above.

An annular polymeric locking collar 8 is disposed on the outsidediameter of RHV 27 distal portion proximal to the point where hub 25meets RHV 27. In this embodiment, rotation of collar 8 locks RHV 27 tohub 25.

FIG. 17 is a schematic diagram of a delivery sheath for delivering amedical electrical device within a coronary venous system, according tothe present invention, from a right-sided venous access point to acoronary sinus. FIG. 18 is a schematic diagram of a delivery sheath fordelivering medical devices within a coronary venous system, according tothe present invention, from a left-sided venous access point to acoronary sinus. FIGS. 17 and 18 illustrate the right and left sidedapproaches, after distal tip 15 of delivery sheath 21, 23 has beenseated in the coronary sinus 930. Introducer guide wire 4 or steerablecatheter 1002 has been removed from lumen of delivery sheath 21, 23. Asillustrated in FIGS. 17 and 18, left-sided venous access point 960 is agreater distance from the ostium of coronary sinus 930 than right-sidedvenous access point 950, and the approach to the coronary sinus 930,from left-sided venous access point, is not as direct. Left-sided venousaccess point 960 may be selected because venous anatomy communicatingfrom right-sided access point 950 may be blocked or because a preferredimplant site 970 for a medical device that is to be connected with amedical electrical lead is on a left side.

Once a passageway formed by lumen of delivery sheath 21, 23 has beenestablished, as illustrated in FIG. 17 or 18, balloon catheter 20 may beadvanced down lumen of delivery sheath 21, 23 and into coronary sinus930 to obtain a venogram. A smaller guide wire or a smaller steerablecatheter or deflection mechanism may be used, within a lumen of ballooncatheter 20 in order to guide balloon catheter 20 distally into coronarysinus 930 from distal tip 15 of delivery sheath 21, 23. After obtainingvenogram, balloon catheter 20 is removed from delivery sheath 21, 23. Anavigation pathway established for delivery of a medical electrical leadis a combination of passageway through delivery sheath 21, 23, intocoronary sinus 930, and venogram obtained using balloon catheter 20.

Medical Electrical Leads and Accessory Tools

FIG. 19 is a plan view of a medical electrical lead having a lumen forreceiving a stylet or a guide wire for delivering a medical electricaldevice within a coronary venous system according to the presentinvention. As illustrated in FIG. 19, a guide wire 46 for introducing amedical electrical lead 40 within the venous system, which issignificantly smaller and of a different construction than introducerguide wire 4, is used with delivery sheath 21 or 23. Guide wire 46,which includes an atraumatic formable tip 47, is the same type used witheither occlusion balloon catheter 20 or an angioplasty balloon catheterhaving a construction well known in the art.

FIG. 19 illustrates guide wire 46 inserted into a lumen 34 of lead 40with formable atraumatic tip 47 protruding from a distal tip 41 of lead40. Lumen 34 of lead 40 has a diameter between approximately 0.014inches and 0.022 inches and extends from a proximal opening 38 at aconnector pin 93 of a connector 50 of lead 40 to a distal opening 39 indistal tip 41 of lead 40. An anchoring sleeve 77 can also be used toreduce corruption of the lead body caused by suturing once lead 40 hasbeen properly positioned within the venous system. Guide wire 46 is usedto steer and guide lead distal tip 41 to a target site in coronary veinsby advancing lead 40 over guide wire 46. Such an embodiment of lead 40,called an “over-the-wire lead”, is disclosed in commonly assigned U.S.Pat. No. 6,192,280 B1, which is incorporated by reference herein itsentirety. A length of guide wire 46 to be used with lead 40 exceeds alength of lead 40, so that tip 47 of guide wire 46 protrudes from distaltip 41 of lead 40, while a proximal portion of guide wire 46 extendsproximally from connector pin 93 A guide wire steering tool 94 may beattached to a proximal portion of guide wire 46 to facilitate steeringof guide wire 46. According to a preferred embodiment of the presentinvention, the maximum diameter of guide wire 46 is betweenapproximately 0.012 inches and 0.020 inches.

FIG. 20 is a schematic of a guide wire atraumatic formable tipprotruding from a lead distal tip of a medical electrical lead andnavigating from the coronary sinus into a branch vein. As illustrated inFIG. 20, guide wire 46, shown by a dashed line, may have been loadedinto lumen of lead 40, illustrated in FIG. 19, with loading device 51,illustrated in FIGS. 24-26, then lead 40 and guide wire 46, together,were advanced through delivery sheath 21 to coronary sinus 930. On theother hand, lead 40 could initially be positioned using a stylet wire(FIG. 21), which is then replaced by guide wire 46, or lead 40 couldinitially be advanced through delivery sheath 21 or 23 and guide wireinserted later. It is therefore understood that many possible orderingof the steps could be used to delivery a medical electrical lead, all ofwhich are merely a matter of operator preference, and therefore thepresent invention is not intended to be limited to preferred ordering ofthe steps utilizing the aspects of the present invention, by rather isintended to include the steps performed in any order that is merely amatter of user preference.

A contrast agent could have been injected down lumen of lead 40 toprovide real-time fluoroscopic guidance as guide wire tip 47 ismanipulated to sub-select branch vein 932. According to the presentinvention, FIG. 20 illustrates a means for navigating lead tip 41 intobranch vein 932. A distal bend 42 of lead 40 provides both guidance andback-up support for guide wire atraumatic formable tip 47 to advanceinto branch vein 932. Once guide wire tip 47 has cannulated branch vein932 and is seated deep enough, lead tip 41 can be pushed forward overguide wire 46 to target site in branch vein 932. Guide wire clip 6,illustrated in FIG. 13, may also be used to manage excess length ofguide wire 46 in a similar manner to that previously described forintroducer guide wire 4 of FIG. 13.

FIG. 21 is a planar view of a stylet wire inserted within a medicalelectrical lead in a system for delivering medical devices within avenous system according to the present invention. As illustrated in FIG.21, a stylet wire 45, which typically has a greater stiffness than guidewire 46, is insertable within central lumen 34 of medical electricallead 40 in place of guide wire 46 to assist in the insertion of lead 40within venous system. Stylet wire 45 includes a distal portion 44, alongwith a stylet knob 48 attached to a proximal end of stylet wire 45.Stylet wire 45 has a length relative to lead 40 such that once styletwire 45 is fully inserted within lumen 34, knob 48 of stylet wire 45engages against connector pin 93 at the proximal end of connector pin50. As a result, knob 48 of stylet wire 46 prevents further insertion ofstylet wire 45 within lumen 34 so that distal portion 44 of stylet wire45 does not extend outward from distal tip 41 of lead 40. Once fullyinserted within lumen 34, stylet wire 45 is subsequently utilized toassist in directing insertion of lead 40 within the venous system.

FIG. 22 is planar side view of a medical electrical lead having a lumenfor receiving a stylet wire and a guide wire in a system for deliveringmedical devices within a venous system according to the presentinvention. FIG. 23 is a cross-sectional side view of a lead distal tipof the medical electrical lead of FIG. 22. As illustrated in FIGS. 22and 23, guide wire 46 and stylet wire 45 of tool kit 10 are alsoinsertable within distal tip 30 of a side-lumen lead 35. Similar toover-the-wire lead 40, side-lumen lead 35 includes connector pin 50 andcentral lumen 34. However, distal tip 30 of lead 35 differs from distaltip 41 of lead 40 since distal tip 30 includes a side lumen 32 thatextends from a side lumen distal end 33 to a side lumen proximal end 43.As illustrated in FIG. 23, guide wire 46 is insertable within side lumen32 by first being inserted at lumen distal end 33 of side lumen 32 in adirection indicated by arrow C, and exiting side lumen 32 at lumenproximal end 43. Once inserted within lumen 32 of lead 35, tip 47 ofguide wire 46 is advanced within venous system, so that once tip 47 ispositioned at a desired location within the coronary sinus, lead 35 isadvanced over guide wire 46 to subsequently position lead distal tip 30at the desired location, as described below.

In addition, as illustrated in FIGS. 22 and 23, stylet wire 45 may alsobe inserted within central lumen 34 of lead 35 at opening 49 ofconnector pin 93 and advanced through lumen 34 to provide additionalstiffness for advancing lead 35 within the venous system. As illustratedin FIGS. 22 and 23, lumen 34 of lead 35 extends from opening 49 atconnector pin 93 at the proximal end of connector 50 to a lumen end wall91 located inside distal tip 30 of lead 35. As a result, once styletwire 45 is fully inserted within lumen 34, distal portion 44 of styletwire 45 engages against end wall 91, preventing stylet wire 45 frombeing advanced outward from distal portion 30 of lead 35. Once insertedwithin lumen 34, stylet wire 45 provides further assistance in directinginsertion of lead 35 within the venous system by providing theadditional stiffness to lead 35 when advancing distal tip 30 along guidewire 46.

FIG. 24 is a schematic diagram of a loading device in a system fordelivering medical devices within a venous system according to thepresent invention. FIG. 25 is a cross-sectional view of the loadingdevice of FIG. 24. As illustrated in FIGS. 24 and 25, a loading device51 in a system for delivering medical devices within a venous systemaccording to the present invention includes a navigation portion 54having an opening 59 formed at a proximal end of loading device 51, analignment lumen 55 positioned within an alignment shaft 52, and anengagement cavity 58 positioned at a distal end of loading device 51.Opening 59 of navigation portion 54 directs a formable atraumatic tip 47of guide wire 46 or distal portion 44 of stylet wire 45 withinnavigation portion 54, which then directs tip 47 or distal portion,respectively, into alignment lumen 55 through a proximal lumen opening53 of alignment lumen 55.

An inner diameter of engagement cavity 58 is sized to snap-fit connectorpin 93 so that a distal lumen opening 56 of loading device 51 is alignedwith an opening 49 of lumen 34 of lead 35, 40 at connector pin 93 forcontinuity between alignment lumen 55 of loading device 51 and leadlumen 34 of lead 35, 40. According to a preferred embodiment of thepresent invention, engagement cavity 58 includes an inner diameterbetween approximately 0.059 inches and 0.061 inches and a length betweenapproximately 0.1 inches and 0.2 inches. An engagement cavity wall 59 ofengagement cavity 58 forms an opening 74 so that engagement cavity wall59 does not completely enclose connector pin 93 when connector pin 93 isinserted within engagement cavity 58. As a result, electrical contactcan be made with connector pin 93 when loading device 51 and connectorpin 93 are fixedly engaged.

FIG. 26 is a schematic diagram of a lead connector fixedly insertedwithin the loading device of FIG. 24. In particular, as illustrated inFIG. 26, once connector pin 93 of connector 50 is fixedly insertedwithin cavity 58 of loading device 51, tip 47 of guide wire 46 or distalportion 44 of stylet wire 45 is inserted at opening 59 of navigationportion 54 in a direction shown by arrow Y, and is directed within lumenopening 53 of alignment lumen 55 by navigation portion 54. Tip 47 ordistal portion 44 is then directed through alignment lumen 55 towardsdistal lumen opening 56. Since opening 56 is aligned with opening 49 oflumen 34 of connector 50 at connector pin 93, tip 47 or distal portion44 passes through openings 56 and 49 and into lumen 34 of connector 50.

According to the present invention, if loading tool 51 is utilized toload stylet wire 45, loading tool 51 and hemostasis valve 27 are sizedso that hemostasis valve 27 can be advanced over loading tool 51 andstylet knob 48 to remove hemostasis valve 27 from lead 35, 40 once lead35, 40 is advanced within the coronary venous system to a target site,as described below.

FIG. 27 is an isometric diagram of an alternate embodiment of a loadingdevice in a system for delivering medical devices within a venous systemaccording to the present invention. As illustrated in FIG. 27, a loadingdevice 151, according to an alternate preferred embodiment of thepresent invention is similar to loading device 51 described above inreference to FIGS. 24 and 25 above. Accordingly, loading device 151fixedly engages with connector pin 93 in a manner as described above inreference to FIGS. 24 and 25, and therefore a description of the similarfeatures, indicated by like reference numerals, is omitted merely forbrevity.

FIG. 28 is a front planar view of the loading device of FIG. 27 in aclosed position. FIG. 29 is a cross-sectional side view of a loadingdevice according to the present invention, taken along cross-sectionallines VII—VII of FIG. 28. As illustrated in FIGS. 27-29, similar toloading device 51, loading device 151 includes engagement cavity 58,alignment shaft 52, and navigation portion 54 forming opening 59.However, according to an alternate embodiment of the present invention,loading device 151 includes a slot 152 extending from the distal end ofalignment shaft 52 to the proximal end of navigation portion 54 atopening 59. As illustrated in FIGS. 27 and 28, slot 152 extends throughan outer wall 153 of navigation portion 54 and through alignment shaft52 to alignment lumen 55 (FIG. 29) and is defined by a first side wall154 of alignment shaft 52 adjacent a second side wall 156 of alignmentshaft 52, and a first side wall 158 of outer wall 153 of navigationportion 54 adjacent a second side wall 160 of outer wall 153 ofnavigation portion 54. Loading device 151 also includes spaced flangeportions 162 and 164 extending from the distal end of alignment shaft 52and terminating along outer wall 153 of navigation portion 54. Adistance between side walls 154-160 of slot 152 is less than thediameter of guide wire 46 or stylet wire 45 when slot 152 of loadingdevice 151 is in a closed position, illustrated in FIG. 28. As a result,loading device 151 cannot be removed directly from guide wire 46 orstylet wire 45 when slot 152 of loading device 151 is in the closedposition.

FIG. 30 is a front planar view of the loading device of FIG. 27 in anopen position. As illustrated in FIG. 30, once pressure is applied atflange portions 162 and 164 in a direction shown by arrows P and P′,respectively, the applied pressure causes flange portions 162 and 164 tobe displaced relative to each other so that a distance between flangeportions 162 and 164 is reduced, and slot 152 of loading device 151 ismoved from the closed position of FIG. 28 to an open position, shown inFIG. 30. The relative displacement of flange portions 162 and 164 causesside walls 154-160 of slot 152 to be displaced so that the distancebetween side walls 154-160 of slot 152 is greater than the diameter ofguide wire 46 or stylet wire 45, so that loading device 151 can bedirectly removed from guide wire 46 or from stylet wire 45 through slot152 when slot 152 is in the open position.

FIG. 31 is a top perspective view of an alternate embodiment of aloading device for loading a guide wire within a medical electrical leadaccording to the present invention. As illustrated in FIG. 31, a loadingdevice 60 according to an alternate embodiment of the present inventionincludes a navigating portion 64 extending from a front end 80 to a backend 82. Navigation portion 64 includes an outer portion 94 and a firstside wall 95 spaced apart from a second side wall 96 to form a slot 65that extends from front end 80 to back end 82 of navigation portion 64.An opening 75 is formed at back end 82 of navigation portion 64 andcouples navigation portion 64 with an engagement cavity 66. Navigationportion 64 receives guide wire 46 as guide wire 46 is inserted within anopening 97 formed at front end 80 and directs guide wire 46, as guidewire 46 is inserted within navigation portion 64, towards opening 75 atback end 82. Guide wire 46 is then directed within engagement cavity 66through opening 75 at back end 82.

Loading device 60 also includes engagement cavity 66 and a lead slot 68for receiving and positioning lead tip 30 and a lead body distal portion31, respectively, within loading device 60. An insertion guide 70 isformed on an upper surface 62 of loading device 60 to assist the user inproperly positioning lead 35 for insertion within engagement cavity 66and lead slot 68. Engagement cavity 66 is shaped to form a line-to-lineor minimum clearance fit around lead distal tip 30 to orientate leaddistal tip 30 to be in a position corresponding to the orientationindicated by insertion guide 70 in order to prevent lead distal tip 30from being corrupted when lead distal tip 30 is inserted withinengagement cavity 66. For example, according to a preferred embodimentof the present invention, engagement cavity 66 is sized to extendapproximately 0.002 inches from lead distal tip 30 when lead distal tip30 is positioned within engagement cavity. On the other hand, lead slot68 is shaped to engage lead body distal portion 31 to snap-fit lead bodydistal portion 31 within lead slot 68.

Back end 82 of navigation portion 64 is located along engagement cavity66 so that back end 82 is aligned with side lumen 32 of lead tip 30 atlumen distal end 33 when lead tip 30 is inserted within engagementcavity 66 in a position corresponding to the orientation indicated byinsertion guide 70 and lead body distal portion 31 is snap-fit to befixedly engaged within lead slot 68. As a result, loading device 60 ofthe present invention enables guide wire 46 to be more easily insertedwithin side lumen 32 of lead tip 30, as will be described below.

FIG. 32 is a cross-sectional side view of a loading device according tothe present invention, taken along cross-sectional line IV—IV of FIG.31. As illustrated in FIGS. 31 and 32, a ramp portion 63 is formed inengagement cavity 66 of loading device 60. Ramp portion 63 extends froma lower end 67 to an upper end 69 to form an upward extending surface 71that directs guide wire 46 out of engagement cavity 66 as guide wire 46is inserted within navigation portion 64 of loading device 60 andthrough side lumen 32 of lead 35 once lead 35 is inserted withinengagement cavity 66 and lead slot 68 of loading device 60, as describedbelow.

FIG. 33 is a top planar view illustrating insertion of a guide wirewithin a medical electric lead using a loading device according to thepresent invention. FIG. 34 is a cross-sectional side view of a loadingdevice according to the present invention, taken along cross-sectionallines V—V of FIG. 33. As illustrated in FIGS. 33 and 34, lead 35 isinserted within loading device 60 by positioning lead tip 30 to match anorientation depicted by insertion guide 70, and once lead tip 30 isoriented in the same position as shown by insertion guide 70, lead 35 ispositioned within loading device 60 by inserting lead tip 30 withinengagement cavity 66 and snap-fitting lead body distal portion 31 withinlead slot 68 of loading device 60 to fixedly engage lead body distalportion 31 within loading device 60.

Once positioned within engagement cavity 66, distal end 33 of side lumen32 of lead 35 is aligned with opening 75 of navigation portion 64. Afterlead 35 is inserted within loading device 60, guide wire 46 is insertedwithin navigation portion 64 in a direction A. By aligning opening 75 ofnavigation portion 64 with distal end 33 of side lumen 32, oncenavigation portion 64 guides wire 46 to be advanced through opening 75,loading device 60 directs guide wire 46 to be advanced within lumendistal end 33 of side lumen 32 of lead 35. As guide wire 46 is advancedthrough side lumen 32, and guide wire 46 subsequently exits side lumen32 at lumen proximal end 43, ramp portion 63 directs guide wire 46 outof engagement cavity 66 as guide wire 46 is extended through side lumen32 of lead tip 30.

According to a preferred embodiment of the present invention, uppersurface 62 of loading device 60 which is approximately one inch squarewith a thickness between approximately 0.15 inches and 0.25 inches,provides a platform that can easily be held by an operator whileengaging lead body distal portion 31 and lead distal tip 30, anddirecting guide wire 46 into side lumen 32. Surface of handlinginterface 62 is also large enough to fit etched insertion guide 70depicting lead body distal portion 31 and distal tip 30 at a 1:1 scale.Insertion guide 70 aids operator in correct placement of lead distal tip30 into engagement cavity 66.

According to the present invention, first side wall 95 is spaced fromsecond side wall 96 at a distance that enables guide wire 46 to beadvanced between first side wall 95 and second side wall 96. As aresult, once guide wire 46 is positioned within side lumen 32, lead 35is removed from loading device 60 with guide wire 46 positioned throughside lumen 32 by removing distal portion 31 and lead distal tip 30 oflead 35 from lead slot 68 and engagement cavity 66, respectively, andremoving guide wire 46 from within navigation portion 64 by advancingguide wire 46 through slot 65.

FIG. 35 is a top planar view illustrating insertion of a guide wirewithin a medical electric lead using an alternate embodiment of aloading device according to the present invention. The alternateembodiment of loading device 60 differs in that loading device 60 isformed to enable loading of guide wire 46 within an over-the-wire lead40 having a lead distal tip 41 with a lumen 43 centrally located toextend through lead 40 from a distal end 61 of lead distal tip 41. Inparticular, as illustrated in FIG. 35, according to the alternateembodiment of the present invention, engagement cavity 66 of loadingdevice 60 is formed to receive lead distal tip 41 to assist in theinsertion of guide wire 46 within lead 40. Lead 40 is inserted withinloading device 60 by positioning lead distal tip 41 to match anorientation depicted by insertion guide 70, and once lead distal tip 41is oriented in the same position as shown by insertion guide 70, lead 40is positioned within loading device 60 by inserting lead tip 41 withinengagement cavity 66 and a lead body distal portion 72 within lead slot68 of loading device 60.

Engagement cavity 66 is shaped to form a line-to-line or minimumclearance fit around lead distal tip 41 to orientate lead distal tip 41to be in a position corresponding to the orientation indicated byinsertion guide 70 in order to prevent lead distal tip 41 from beingcorrupted when inserted within engagement cavity 66. For example,according to a preferred embodiment of the present invention, engagementcavity 66 is sized to extend approximately 0.002 inches from lead distaltip 41 when lead distal tip 41 is positioned within engagement cavity66. On the other hand, lead slot 68 is shaped to engage lead body distalportion 72 to snap-fit lead body distal portion 72 within lead slot 68.In addition, similar to the preferred embodiment described above inreference to FIGS. 31-34, back end 82 of navigation portion 64 islocated along engagement cavity 66 so that back end 82 is aligned withlumen 43 at lumen distal end 61 when lead distal tip 41 is insertedwithin engagement cavity 66 in a position corresponding to theorientation indicated by insertion guide 70 and lead body distal portion72 is snap-fit to be fixedly engaged within lead slot 68. As a result,loading device 60 of the present invention enables guide wire 46 to bemore easily inserted within lumen 43 of lead distal tip 41.

After lead 40 is inserted within loading device 60, guide wire 46 isinserted within navigation portion 64 at opening 97 in direction B, withnavigation portion 64 directing guide wire 46 towards opening 75 so thatguide wire 46 is inserted within lead distal tip 41 at lumen distal end61 of lumen 43. Guide wire 46 is directed into lumen 43 at distal tip41, passes through lumen 43, and travels out proximal opening inconnector pin 50 (FIG. 21). Once guide wire 46 is positioned withinlumen 43, lead 40 is removed from loading device 60 with guide wire 46positioned through lumen 43 by removing lead distal tip 41 and distalportion 72 of lead 40 from engagement cavity 66 and lead slot 68,respectively, and removing guide wire 46 from within navigation portion64 by advancing guide wire 46 through slot 65.

FIG. 36 is a schematic diagram of positioning of a guide wire 46 withina branch vein. According to the present invention, FIG. 36 illustrates asituation in which guide wire 46 was used to deliver venogram ballooncatheter 20, illustrated in FIG. 13, through delivery sheath 21. Afterobtaining venogram with balloon catheter 20, atraumatic formable tip 47of guide wire 46 is advanced to a target site in branch vein 933;positioning of atraumatic formable tip 47 may have been facilitated byadditional injections of a contrast agent down a lumen of ballooncatheter 20. Guide wire 46 is left in position when balloon catheter 20is removed. Proximal end of guide wire 46 may be directed into sidelumen 32 of lead tip 30, illustrated in FIGS. 21 and 22 and 32, usingloading device 60 as illustrated in FIG. 31. Lead tip 30 is pushed alongguide wire 46 until lead tip 30 reaches the target site in branch vein933. As illustrated in FIGS. 21 and 22, stylet wire 45 may be insertedinto central lumen 34 of lead 35 to provide additional stiffness formoving lead distal tip 30 along guide wire 46.

Guide wire 46 and/or stylet wire 45 may be removed before deliverysheath 21 is removed, however a preferred method is to retain guide wire46 and/or stylet wire 45 until after delivery sheath 21 is removed. Aretained stylet wire 45 helps maintain stiffness in lead 35 that can beused to hold lead tip 30 in position while delivery sheath 21 is beingremoved. If removal of delivery sheath 21 dislodges lead tip 30, aretained guide wire 46 will help to re-position lead tip 30.

FIGS. 37 and 38 are schematic diagrams illustrating removal of adelivery sheath and a rotatable hemostasis valve from an implanted leadbody according to the present invention. Once insertion of the lead hasbeen completed, delivery sheath 21, 23 must be slit and peeled off fromlead body 35, 40 since outer diameters of an industry standard IS-1connector 50 and an anchoring sleeve 77, mounted on lead body 73, aresignificantly larger than a diameter of lead body 35, 40 and will notfit through lumen of delivery sheath 21. In addition, hemostasis valve27 must also be removed from lead body 35, 40. According to the presentinvention, hemostasis valve 27 is first removed from hub 25 of sheath21, 23 by rotating collar 37 to unlock hemostasis valve 27 from hub 25.Once unlocked from hub 25, hemostasis valve 27 is slid over lead 35, 40to advance hemostasis valve 27 from an attached position, illustrated inFIG. 37, to an unattached position, illustrated in FIG. 38, so thathemostasis valve 27 is slid over anchoring sleeve 77 and connector 50,and over knob 48 of stylet wire 45, if stylet wire 45 is utilized.

FIG. 39 is partial section plan view of a hemostasis valve according tothe present invention. As illustrated in FIG. 39, in order to enablehemostasis valve 27 to be removed from lead 35, 40 by being slid overconnector 50, hemostasis valve 27 of the present invention includes anon-standard Touhy Borst valve 28 having an adjustable lumen 29 and anon-standard male luer fitting 16 within a locking collar 8. Accordingto the present invention, a minimum internal diameter of adjustablelumen 29 is small enough to seal on lead body 63, approximately 0.050inches in diameter, and a maximum internal diameter of adjustable lumenis approximately 0.2 inches in diameter. Furthermore, an inner diameter(shown with dashed line) of non-standard male luer fitting 16 isapproximately 0.2 inches. Both the maximum diameter of adjustable lumen29 and inner diameter of male luer fitting 16 are large enough to allowpassage of lead anchoring sleeve 77 and lead connector 50 as RHV 27 isremoved from delivery sheath 21, 23.

Returning to FIG. 38, according to the present invention, stylet wire 45includes knob 48 having a diameter large enough so that knob 48 cannotpass into lumen of lead but small enough so that knob 48 can passthrough maximum diameter of adjustable lumen 29 of Touhy Borst valve 28and inner diameter of male luer fitting 16.

FIG. 40 is a flowchart of a method of delivering a medical electricallead within a coronary sinus according to the present invention. Asillustrated in FIG. 40, a method of delivering a medical electrical leadwithin a coronary sinus according to the present invention includesestablishing venous access, Step 500. Once venous access is established,a delivery sheath is chosen corresponding to the desired approach to thecoronary sinus, Step 502, and the chosen delivery sheath is positionedwithin the venous access, Step 504. For example, if a right-sidedapproach is preferred, delivery sheath 21 is chosen, and if a left-sidedapproach is preferred, delivery sheath 23 would be chosen. The lead isinserted within a loading device, Step 506, and a guide wire is insertedwithin a navigation portion of the loading device, Step 508, thenavigation portion directing the guide wire within a lumen of the lead.The guide wire is advanced through a slot, formed by a first side wallspaced from a second side wall and extending along an outer portion ofthe navigation portion, to remove the lead having the guide wireinserted therein from the loading device, Step 510. The distal tip ofthe medical electrical lead is advanced through the hemostasis valve andwithin the delivery sheath, Step 512, and advancement of the distal tipof the medical electrical lead is guided to a target site within thecoronary venous system using the guide wire, Step 512.

In addition, the method of delivering a medical electrical lead within acoronary sinus according to the present invention may also includecoupling rotatable hemostasis valve 27 at proximal portion 14 ofdelivery sheath 21 or 23, and decoupling the hemostasis valve fromdelivery sheath 21 or 23 and advancing hemostasis valve 27 overconnector 50 of the medical electrical lead 35, 40 to remove hemostasisvalve 27 from lead 35, 40.

In addition, according to the present invention, stylet wire 45 may beinserted within lead 35 to assist in guiding the advancement of lead 35to the target site, and the step of decoupling hemostasis valve 27 wouldthen include advancing hemostasis valve 27 over stylet knob 48 in orderto remove hemostasis valve 27 from lead 35. In the same way, ifanchoring sleeve 77 is utilized with lead 35 or 40, hemostasis valve 27is also advanced over anchoring sleeve 77. Furthermore, if loading tool51 is utilized to load stylet wire 45 within lead 35, decoupling of thehemostasis valve 27 would then include advancing hemostasis valve 27over stylet knob 48 and loading tool 51 in order to remove hemostasisvalve 27 from lead 35.

Many alterations and modifications may be made by those having ordinaryskill in the art without departing from the spirit and scope of theinvention. The illustrated variations have been used only for thepurposes of clarity and should not be taken as limiting the invention asdefined by the following claims. For example, although delivery sheaths21, 23 are described with distal portions 12, 13 illustrated in FIG. 13,combinations of delivery sheaths with other styles of distal curvaturethat are well known in the art, such as Judkins and Amplatz, may beincluded in alternative embodiments of tool kit 10.

We claim:
 1. A loading device for loading a guide wire within a medicalelectrical lead having a lead distal tip and a lumen for receiving theguide wire, the loading device comprising: a navigation portion, havingan outer portion, and extending from a front end to a back end, andhaving an opening formed at the back end; an engagement cavity receivingand properly orienting the lead distal tip to align the lumen of thelead with the opening of the navigation portion during the loading ofthe guide wire within the lead; and a first side wall spaced from asecond side wall to form a slot extending along the outer portion fromthe front end to the back end of the navigation portion, wherein theguide wire is advanced through the slot as the lead having the guidewire loaded therein is removed from the loading device.
 2. The loadingdevice of claim 1, further comprising an insertion guide positioned onthe loading device to properly position the lead distal tip within theengagement cavity.
 3. The loading device of claim 1, wherein theengagement cavity is shaped to form a minimum clearance fit about thelead distal tip.
 4. The loading device of claim 3, wherein the leadincludes a lead body distal portion extending from the lead distal tip,wherein the lead body distal portion is fixedly engaged within theloading device.
 5. The loading device of claim 1, further comprising: afirst opening formed at the front end of navigation portion; and asecond opening formed at the back end of navigation portion and couplingthe navigation portion with the engagement cavity, wherein theengagement cavity aligns the lumen of the lead with the second opening.6. The loading device of claim 1, wherein the engagement cavity is sizedto extend approximately 0.002 inches from the lead distal tip when thelead distal tip is inserted within the engagement cavity.
 7. The loadingtool of claim 1, wherein the lead is a side-lumen lead.
 8. The loadingtool of claim 7, further comprising a ramp portion directing the guidewire out of the engagement cavity as guide wire is extended through theside lumen lead.
 9. The loading tool of claim 1, wherein the lead is anover-the-wire lead.
 10. A method of delivering a medical electrical leadwithin a coronary venous system, comprising the steps of: establishingvenous access to the coronary venous system using an introducer toolkit; choosing a delivery sheath from a plurality of delivery sheathscorresponding to a desired approach to a coronary sinus of the coronaryvenous system; positioning the delivery sheath within the venous access;inserting the lead within a loading device; inserting a guide wirewithin a navigation portion of the loading device, the navigationportion directing the guide wire within a lumen of the lead; advancingthe guide wire through a slot formed by a first side wall spaced from asecond side wall and extending along an outer portion of the navigationportion to remove the lead having the guide wire inserted therein fromthe loading device; inserting the distal tip of the medical electricallead within the delivery sheath; and guiding advancement of the distaltip of the medical electrical lead to a target site within the coronaryvenous system using the guide wire.
 11. The method of claim 10, furthercomprising the steps of: coupling a hemostasis valve over a proximalportion of the delivery sheath; and decoupling the hemostasis valve fromthe delivery sheath and advancing the hemostasis valve over a connectorof the medical electrical lead to remove the hemostasis valve from themedical electrical lead.
 12. The method of claim 11, further comprisingthe step of inserting a stylet, having a stylet knob, within the lead toassist in guiding the advancement of the lead to the target site, andwherein the step of decoupling the hemostasis valve includes advancingthe hemostasis valve over the stylet knob to remove the hemostasis valvefrom the medical electrical lead.
 13. The method of claim 11, whereinthe step of decoupling the hemostasis valve includes advancing thehemostasis valve over an anchoring sleeve positioned on the lead. 14.The method of claim 11, wherein the step of positioning the deliverysheath includes inserting the delivery sheath within the coronary venoussystem using one of a steerable catheter and an introducer guide wire.15. The method of claim 14, further comprising the step of securingexcess length of one of the guide wire and the introducer guide wire toprevent the excess length from entering a sterile field while allowingrepositioning of the guide wire and the introducer guide wire.
 16. Themethod of claim 11, wherein the connector is an IS-1 connector.
 17. Themethod of claim 11, wherein the plurality of delivery sheaths include aleft-sided venous access delivery sheath and a right-sided deliverysheath.
 18. The method of claim 11, wherein the medical electrical leadis one of an over-the-wire lead and a side-lumen lead.
 19. A system fordelivering a medical electrical lead within a coronary venous system,the medical electrical lead extending from a connector to a distal tipand having a lead lumen located at the distal tip, the systemcomprising: an introducer kit establishing venous access to the coronaryvenous system; a plurality of delivery sheaths, each corresponding to adesired approach to a coronary sinus of the coronary venous system,establishing a navigation pathway within the coronary venous systemthrough the venous access; a hemostasis valve coupled to a deliverysheath of the plurality of delivery sheaths; and a loading deviceloading a guide wire insertable within the lead lumen, the loadingdevice including a navigation portion, having an outer portion, andextending from a front end to a back end, and having an opening formedat the back end, an engagement cavity receiving and properly orientingthe lead distal tip during the loading of the guide wire within thelead, and a first side wall spaced from a second side wall to form aslot extending along the outer portion from the front end to the backend of the navigation portion, wherein the guide wire is advancedthrough the slot as the lead having the guide wire loaded therein isremoved from the loading device, and wherein the guide wire guidesdelivery of the distal tip of the medical electrical lead to a targetsite within the coronary venous system through the hemostasis valve andthe delivery sheath, wherein, subsequent to the distal tip beingdelivered to the target sight, the hemostasis valve is advanced over theconnector of the medical electrical lead to remove the hemostasis valvefrom the medical electrical lead.
 20. The system of claim 19, furthercomprising an insertion guide positioned on the loading device toproperly position the lead distal tip within the engagement cavity. 21.The system of claim 19, wherein the engagement cavity is shaped to forma minimum clearance fit about the lead distal tip.
 22. The system ofclaim 21, wherein the lead includes a lead body distal portion extendingfrom the lead distal tip, wherein the lead body distal portion isfixedly engaged within the loading device.
 23. The system of claim 19,further comprising: a first opening formed at the front end ofnavigation portion; and a second opening formed at the back end ofnavigation portion and coupling the navigation portion with theengagement cavity, wherein the engagement cavity aligns the lumen of thelead with the second opening.
 24. The system of claim 22, wherein theengagement cavity is sized to extend approximately 0.002 inches from thelead distal tip when the lead distal tip is inserted within theengagement cavity.
 25. The system of claim 19, further comprising a rampportion positioned within the engagement cavity, wherein the lead is aside-lumen lead and the ramp portion directs the guide wire out of theengagement cavity as guide wire is extended through the side lumen lead.26. The system of claim 19, further comprising a stylet, having a styletknob, inserted within the lead to assist in guiding the advancement ofthe lead to the target site, wherein the hemostasis valve is advancedover the stylet knob to remove the hemostasis valve from the medicalelectrical lead.
 27. The system of claim 26, further comprising ananchoring sleeve position along the lead, wherein the hemostasis valveis advanced over the anchoring sleeve to remove the hemostasis valvefrom the medical electrical lead.
 28. The system of claim 19, whereinthe tool kit includes a steerable catheter and an introducer guide wire,and wherein the delivery sheath is inserted within the coronary venoussystem through the venous access using one of the steerable catheter andthe introducer guide wire.
 29. The system of claim 28, furthercomprising a guide wire clip capable of being positioned in one of anon-engaging open position and an engaging closed position, the guidewire clip securing excess length of one of the guide wire and theintroducer guide wire to prevent the guide wire and the introducer guidewire from entering a sterile field while allowing repositioning of theguide wire and the introducer guide wire when the guide wire clip is inthe closed position.
 30. The system of claim 19, wherein the pluralityof delivery sheaths include a left-sided venous access delivery sheathand a right-sided delivery sheath.
 31. The system of claim 19, whereinthe medical electrical lead is one of an over-the-wire lead and aside-lumen lead.
 32. The system of claim 19, wherein the connector is anIS-1 connector.